JP2019191326A - Image formation apparatus - Google Patents

Abstract

To provide an image formation apparatus which efficiently arranges a test pattern image on a recording material without reducing the detection accuracy when detecting the image defect or the like.SOLUTION: An image formation apparatus includes a test pattern image generation unit which generates a plurality of types of test pattern images, and controls the positions of the test pattern images so as to arrange the generated test pattern images in a region where an image can be formed on a sheet P. The test pattern image generation unit decides the size of the output image based on the size of the sheet P (S101), and arranges the test pattern images on the output image based on the size of the output image and the sizes of the test pattern images (S102-S107).SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus such as a laser beam printer, a copying machine, and a facsimile using an electrophotographic process.

  Conventionally, for example, a laser beam printer using an electrophotographic process that uniformly charges the surface of a photoreceptor, exposes the surface of the photoreceptor to form an electrostatic latent image, and visualizes the electrostatic latent image with toner, There are image forming apparatuses such as copying machines and facsimiles. In such an image forming apparatus, a test pattern image is output onto a recording material, the test pattern image is scanned by a sensor such as a scanner, and the scanned result is compared with an original image (hereinafter referred to as an original image). Systems for detecting image defects are known. For example, in Patent Document 1, in order to improve the accuracy of predicting the replacement part timing, a test pattern image is output, the master image is compared with the read result of the output image to be inspected, and the replacement part is abnormal. There is a configuration for determining whether or not. Further, for example, in Patent Document 2, an image reading device is arranged in an image forming apparatus, and a test pattern image output to a recording material can be scanned without setting the image reading device again. The configuration is known.

Japanese Patent Laying-Open No. 2015-034807 JP 2017-116607 A

  In order to detect an image defect, it is necessary to use a specific test pattern image depending on the factor. For example, when it is desired to detect an image defect in which a part of an image is not formed, an image in which a certain area is filled (hereinafter referred to as a solid image) is used as a test pattern image. Further, for example, when it is desired to detect an image defect in which a high density streak is generated in the output image, a halftone image formed with a constant density is used instead of a solid image. In addition, the test pattern image needs to have a single color and a specific length and width in order to specify the cause of image failure. For example, in the case of an image defect due to the photoconductor, the test pattern image needs to have an image length corresponding to at least one rotation of the surface of the photoconductor in order to detect the image defect. Furthermore, in the case of a color image forming apparatus that superimposes different colors depending on a plurality of photoconductors, it is necessary to form a test pattern image on a recording material independently for each color.

  As described above, the diagnostic method for detecting an image defect and the test pattern image used for the diagnosis need to be changed according to the image defect to be detected. Further, when outputting test pattern images to a recording material, the number of test pattern images that can be arranged on the recording material is limited. Under these conditions, when image defect detection is performed to inspect the status of a replacement part, the type and number of test pattern images to be detected and the test pattern image to be formed vary depending on the status of the replacement part. End up.

  The present invention has been made under such circumstances, and it is an object of the present invention to efficiently arrange test pattern images on a recording material without degrading detection accuracy when detecting an image defect or the like. To do.

  In order to solve the above-described problems, the present invention has the following configuration.

  (1) An image forming apparatus including an image forming unit that forms an image for inspection for inspecting an image forming state on a recording material. The image forming apparatus generates a plurality of types of the images for inspection, and generates the generated images for inspection. Control means for controlling the position of the inspection image so as to be arranged in an area where an image can be formed on the recording material, the control means determines the size of the area based on the size of the recording material, An image forming apparatus, wherein the inspection image is arranged in the region based on the size of the region and the size of the inspection image.

  According to the present invention, when an image defect or the like is detected, a test pattern image can be efficiently arranged on a recording material without reducing detection accuracy.

1 is a diagram illustrating an overview of image forming apparatuses according to first and second embodiments. FIG. 3 is a block diagram illustrating a control configuration of the image forming apparatus according to the first and second embodiments. The figure which shows arrangement | positioning of the test pattern image for the image diagnosis of Example 1. FIG. Flowchart showing image diagnosis processing of Embodiment 1 The figure which shows arrangement | positioning of the test pattern image for the image diagnosis of Example 2. FIG. The figure which shows arrangement | positioning of the test pattern image for the image diagnosis of Example 2. FIG. Flowchart showing image diagnosis processing of Embodiment 2

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. . Further, the materials, shapes, etc. of the members once described in the following description are the same as those in the first description unless otherwise described.

<Configuration of image forming apparatus and printing operation>
In the first embodiment, in one image forming apparatus, replacement parts provided in the image forming apparatus based on image data to be printed on a sheet as a recording material and data obtained by scanning the printed sheet. A method for determining whether or not is functioning normally will be described. First, an outline of the overall configuration of a color electrophotographic image forming apparatus used in Embodiment 1 will be described with reference to FIG. The image forming apparatus shown in the first embodiment is a laser printer (hereinafter referred to as a printer) 100 using an electrophotographic image forming process. The printer 100 shown in FIG. 1 includes process stations (hereinafter referred to as cartridges) 5Y, 5M, 5C, and 5K, which are image forming units that are detachable from the printer 100. The four cartridges 5Y, 5M, 5C, and 5K have the same structure, but images with toners (developers) of different colors, that is, yellow (Y), magenta (M), cyan (C), and black (K). It differs in that it forms. In the following description, the YMCK symbol is omitted unless a specific cartridge is described. Each cartridge 5 includes a toner container 23, a photosensitive drum 1 as a photoreceptor, a charging roller 2, a developing roller 3, a cleaning blade 4, and a waste toner container 24. An exposure device 7 is disposed below the cartridge 5 and performs exposure on the photosensitive drum 1 based on the image signal. The toner container 23 and the developing roller 3 function as developing means.

  The photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the charging roller 2 during the rotation process. The photosensitive drum 1 is exposed by the exposure device 7 to form an electrostatic latent image corresponding to each color of the target color image. Here, the electrostatic latent image corresponding to yellow corresponds to an electrostatic latent image corresponding to the first color (hereinafter referred to as a first color component image). The electrostatic latent image corresponding to magenta corresponds to an electrostatic latent image corresponding to the second color (hereinafter referred to as a second color component image). The electrostatic latent image corresponding to cyan corresponds to an electrostatic latent image corresponding to the third color (hereinafter referred to as a third color component image). The electrostatic latent image corresponding to black corresponds to an electrostatic latent image corresponding to the fourth color (hereinafter referred to as a fourth color component image).

  The charging roller 2 is driven to rotate as the photosensitive drum 1 rotates. The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing roller 3 of the cartridge 5. Each color toner is attached to the electrostatic latent image on the photosensitive drum 1 through the developing roller 3 and developed as a toner image. The toner in each toner container 23 is a negatively charged non-magnetic one-component toner, and development of the electrostatic latent image is performed by a non-magnetic one-component contact development method. A developing voltage is applied to the developing roller 3 by a developing voltage power source (not shown), whereby development is performed.

  The intermediate transfer belt unit includes an intermediate transfer belt 8, a drive roller 9, and a secondary transfer counter roller 10. Further, a primary transfer roller 6 is disposed inside the intermediate transfer belt 8 so as to face each photosensitive drum 1, and a positive primary transfer voltage is applied by a primary transfer voltage power source (not shown). When the driving roller 9 is rotated by a motor (not shown), the intermediate transfer belt 8 is rotated, and the secondary transfer counter roller 10 is also rotated in accordance with the rotation. Each photosensitive drum 1 rotates in the arrow direction (clockwise direction), the intermediate transfer belt 8 rotates in the arrow A direction, and a positive primary transfer voltage is applied to the primary transfer roller 6. As a result, the toner image on the photosensitive drum 1 is sequentially transferred onto the intermediate transfer belt 8 (on the belt) from the toner image on the photosensitive drum 1Y. Thereafter, the toner images of the four colors are overlapped on the intermediate transfer belt 8 and conveyed to the secondary transfer roller 11. The cleaning blade 4 of the photosensitive drum 1 is in pressure contact with the photosensitive drum 1 and removes toner remaining on the surface of the photosensitive drum 1 without being transferred to the intermediate transfer belt 8 and other residues on the photosensitive drum 1 (on the photosensitive member). To do.

  The paper feeding / conveying device 12 includes a paper feeding roller 14 that feeds the paper P from a paper feeding cassette 13 (paper feeding unit) that stores the paper P, and a pair of conveying rollers 15 that transport the fed paper P. . The paper P transported from the paper feeding / conveying device 12 is transported to the secondary transfer roller 11 by a registration roller pair (hereinafter referred to as a registration roller pair) 16. In the transfer from the intermediate transfer belt 8 to the paper P, a four-color toner image on the intermediate transfer belt 8 is transferred to the conveyed paper P by applying a positive voltage to the secondary transfer roller 11. (Hereinafter referred to as secondary transfer). The cleaner 21 removes the toner remaining on the intermediate transfer belt 8 after the secondary transfer.

  The sheet P after the toner image is transferred is conveyed to a fixing device 17 that is a fixing unit. The fixing device 17 is a film heating system that includes a fixing heater 30, a fixing roller 18 including a temperature sensor 31 that measures the temperature of the fixing heater 30, and a pressure roller 19 that presses the fixing roller 18. It is a fixing device. Then, the toner image is fixed by heating and pressurizing the paper P, and is discharged out of the printer 100 (outside the apparatus) as an image formed product (printed paper or the like). The printer 100 can perform double-sided printing on the paper P. Further, the printer 100 has an image reading unit 2050 as a reading unit in a conveyance path for double-sided printing (hereinafter referred to as a double-sided conveyance path), and the image reading unit 2050 acquires a scan image of the paper P. Provide functionality. The image reading unit 2050 is arranged so as to read the surface of the paper P when the image is formed on the first surface of the paper P and then conveyed on the double-sided conveyance path. In the case of double-sided printing in which printing is also performed on the back side, which is the second side of the paper P, the double-sided flapper 50 is first transported on both sides after the trailing edge of the paper P that has passed through the fixing unit 17 passes the position of the double-sided flapper 50. Switch to the roadside. Further, the rotation direction of the discharge roller pair 20 is switched to the double-sided conveyance path side by a reversing clutch 2024 (see FIG. 2) described later that determines the rotation direction of the discharge roller pair 20. As a result, the transport direction of the paper P is reversed, and the paper P is transported to the duplex transport path. In the duplex conveyance path, the sheet P is conveyed by the duplex conveyance roller pair 51 and the main body merging roller pair 53, and the sheet P is conveyed to the registration roller pair 16. After the registration roller pair 16, the same processing as the surface of the paper P is executed, and the paper P passes through the fixing device 17 and is then discharged out of the printer 100.

  When the image reading unit 2050 scans the surface of the paper P, the paper P is conveyed to the double-sided conveyance path as in the case of double-sided printing described above. The image reading unit 2050 starts reading the surface of the paper P at the timing when the leading edge of the paper P passes through the double-sided conveyance roller pair 51. The image reading unit 2050 includes a light emitting element (not shown) and a CIS (CONTACT IMAGE SENSOR) (not shown). The image reading unit 2050 reads an image of the paper P moving on the image reading unit 2050 as a time-series electric digital pixel signal (hereinafter referred to as a pixel signal). The image reading unit 2050 accumulates pixel signals of the read image in a memory in the image reading unit 2050. The paper P for which image reading by the image reading unit 2050 has been completed passes through the paper transport path and is discharged outside the apparatus.

<Block diagram>
FIG. 2 is a control block diagram of the printer 100 according to the first embodiment. The printer 100 is divided into a controller 1000 and an engine 2000. The controller 1000 is connected to the engine 2000 which is an image output device, and on the other hand, is connected to the LAN 1013 to input / output image information and device information. The controller control unit 1010 is a CPU that controls the entire system, and includes a RAM (not shown) that is a work memory and a ROM (not shown) that stores a boot program. An HDD 1020 is a hard disk drive that stores system software, image data, and the like. The pixel measurement unit 1040, the read image determination unit 1041 as a diagnostic unit, and the test pattern image generation unit 1042 are functions of software executed by the controller control unit 1010 stored in the HDD 1020. The operation unit I / F 1011 is an interface unit with an operation unit 1014 having a touch panel, for example, and outputs image data displayed on the operation unit 1014 to the operation unit 1014. Also, it plays a role of transmitting information input by the system user from the operation unit 1014 to the controller control unit 1010. A network I / F 1012 is connected to the LAN 1013 and inputs / outputs information. The raster image processor 1030 expands a PDL (Page Description Language) code into a bitmap image. The engine image processing unit 1034 converts the bitmap image developed by the raster image processor 1030 into image data to be transmitted to the engine 2000 by performing correction, resolution conversion, and the like. The read image processing unit 1033 performs correction, processing, editing, and the like on the input image data read by the image reading unit 2050.

  The controller control unit 1010 and the engine control unit 2010 are connected via an engine I / F 1100, and an operation instruction and image data are communicated from the controller control unit 1010 to the engine control unit 2010 via the engine I / F 1100. Do. The engine 2000 is an image output device. The engine control unit 2010 is connected to the controller control unit 1010 via the engine I / F 1100, operates each unit of the engine 2000 according to an instruction from the controller 1000, and prints on the paper P. The engine control unit 2010 is a CPU that controls the entire engine, and includes a RAM (not shown) and a ROM (not shown) in which a program for controlling the engine 2000 is stored. The replacement part management unit 2040 is a function of a program executed by the engine control unit 2010 stored in a ROM (not shown).

  The engine control unit 2010 is connected to the fixing unit 2020, the motor drive unit 2021, the exposure control unit 2022, the double-sided flapper 50, the reverse clutch 2024, and the like. The fixing unit 2020 supplies power to the fixing device 17. The motor driving unit 2021 drives a motor for driving the photosensitive drum 1, the intermediate transfer belt 8, the pressure roller 19, and the like in the printer 100. The exposure control unit 2022 controls the exposure apparatus 7. The double-sided flapper 50 switches the transport path of the paper P during double-sided printing. The double-sided flapper 50 also switches the conveyance path of the paper P to the double-sided conveyance path when the image reading unit 2050 reads a test pattern image that is an inspection image on the paper P. The reverse clutch 2024 switches the rotation direction of the discharge roller pair 20. The engine control unit 2010 prints a toner image on the paper P by an electrophotographic image forming process based on image data transmitted from the controller 1000 via the engine I / F 1100.

  The engine control unit 2010 is connected to the image reading unit 2050. The engine control unit 2010 includes an image reading control unit 2041, and the image reading control unit 2041 controls the image reading unit 2050. When scanning an image carried on the surface of the sheet P, the engine control unit 2010 outputs a reading instruction to the image reading unit 2050 via the image reading control unit 2041 before the sheet P reaches the image reading unit 2050. To do. After the trailing edge of the paper P passes through the image reading unit 2050, the engine control unit 2010 notifies the controller control unit 1010 that the image reading has been completed. The controller control unit 1010 acquires scan image data accumulated in the image reading unit 2050 via the engine I / F 1100. Each function of the controller 1000 and the engine 2000 may be realized by each CPU executing various control programs, or a part or all of the functions are performed on a dedicated circuit (ASIC) for a specific application. You may let them.

<Replacement parts status and diagnostic imaging>
When the remaining amount of toner in the toner container 23 (hereinafter referred to as the remaining amount of toner) is reduced, or due to toner deterioration due to friction caused by stirring, and further due to wear of the photosensitive drum 1, the required toner image density is reduced. It may be difficult to obtain. In addition, when these phenomena occur, there is a risk that image defects such as white spots in the toner image may occur. In order to prevent these problems, the printer 100 is configured to measure the remaining amount of toner and the wear amount of the photosensitive drum 1. Note that when the amount of wear of the photosensitive drum 1 reaches a predetermined amount, it is expressed that the photosensitive drum 1 has reached the end of its life. When the photosensitive drum 1 reaches the end of its life, the required toner image density cannot be obtained, and the cartridge 5 must be replaced. In addition, the replacement part of the printer 100 is not limited to the photosensitive drum 1, and the replacement part needs to be replaced when the replacement part reaches the end of its life.

(Measurement of remaining toner)
The measurement of the remaining amount of toner uses a prediction method based on the number of pixels having a density equal to or higher than a predetermined value for outputting a color (hereinafter referred to as the number of pixels). The pixel measurement unit 1040 of the controller control unit 1010 counts the number of pixels that output each color of YMCK from the bitmap image developed from the PDL code by the raster image processor 1030. When the controller control unit 1010 issues a print instruction to the engine control unit 2010, the controller control unit 2010 notifies the engine control unit 2010 of the number of pixels of the image to be printed. A replacement part management unit 2040 that is a calculation unit of the engine control unit 2010 calculates the remaining amount of toner using a value obtained by integrating the number of pixels notified from the engine control unit 2010. The measurement of the remaining amount of toner is not limited to the method described above. For example, a method of detecting a toner remaining amount based on a detection result of a sensor or the like provided with a sensor or the like for detecting the amount of toner in the toner container 23 may be used.

(Measurement of photosensitive drum life)
The amount of wear of the photosensitive drum 1 indicating the degree of wear of the photosensitive drum is estimated from the cumulative number of rotations of the photosensitive drum 1. The replacement part management unit 2040 monitors the driving state of the motor that drives the photosensitive drum 1 via the motor driving unit 2021. The replacement part management unit 2040 calculates the cumulative number of revolutions of the photosensitive drum 1 based on the driving time and the driving speed, and calculates the life of the photosensitive drum 1 based on the ratio to the cumulative number of revolutions until the expected life is reached. The replacement part management unit 2040 notifies the controller remaining amount and the life of the photosensitive drum 1 to the controller control unit 1010. The controller control unit 1010 displays a message prompting the user to replace the cartridge 5 on the operation unit 1014 according to the remaining toner amount notified from the engine control unit 2010 and the life of the photosensitive drum 1.

  However, depending on the type of image to be printed and the atmospheric environment of the printer 100, the remaining amount calculated by the above-described method for the remaining amount of toner and the wear amount of the photosensitive drum 1 may not always have a correlation. Accordingly, as the number of printed sheets is increased, errors accumulate, so the remaining amount of toner and the life of the photosensitive drum 1 may not be determined with high accuracy. In addition, even after notifying that the replacement part has reached the end of its life, a replacement part that has reached the end of its life may be used. Therefore, the printer 100 according to the first embodiment needs to output a test pattern image and inspect the image formation state when the cartridge 5 has reached or is nearing the end of its life. It is confirmed whether or not an image defect has occurred by reading the state of the test pattern image. The test pattern image is generated according to the type of image defect. If an image defect occurs due to the life of the replacement part, a test pattern image suitable for the replacement part is generated so that the test pattern image can determine the image defect that occurs due to the life of the replacement part. The Hereinafter, the operation of determining whether or not an image defect has occurred using the test pattern image is referred to as image diagnosis (diagnosis).

<Test pattern image>
The test pattern image is a halftone image that is output at a uniform monochrome density (for example, a density of 50%), and has Y, M, C, and K test pattern images. The test pattern size is the full output image width and the image length is the photosensitive drum 1 so that it is possible to detect the image defect that has occurred at any position on the photosensitive drum 1. The image is longer than one round. The image length is the length in the rotation direction (also referred to as the sub-scanning direction) of the photosensitive drum 1, and the image width is the length in the rotation axis direction (also referred to as the main scanning direction) of the photosensitive drum 1. The printer 100 according to the first embodiment assumes that a paper having a letter size (215.9 mm × 279.4 mm) is transported in a direction orthogonal to the transport direction of the paper P, and is up to 216 mm in the width direction. Can be conveyed. Further, the length of one circumference of the photosensitive drum 1 used in Example 1 is 80 mm. Therefore, in the first embodiment, for example, the test pattern image has an image width of 212 mm and an image length of 85 mm. The image width is 4 mm shorter than 216 mm in order to provide a margin of 2 mm at both ends. The width of 212 mm is the maximum width, and the actual test pattern image is changed to the maximum width that can be formed according to the width of the paper P to be transferred.

  The replacement part management unit 2040 notifies the controller control unit 1010 of an image diagnosis request for the cartridge 5 when the remaining amount of toner or the photosensitive drum 1 reaches the end of its life. The test pattern image generation unit 1042 serving as a control unit outputs a test pattern image for the requested color cartridge 5, that is, forms a test pattern image for the requested color cartridge 5 on the surface of the paper P. . Hereinafter, forming a predetermined image on the paper P is referred to as outputting the predetermined image. The paper P on which the test pattern image is formed is conveyed to the image reading unit 2050 on the double-sided conveyance path, and the image reading unit 2050 scans (reads) the test pattern image on the paper P as an output result. Data of the scanned test pattern image on the paper P (hereinafter referred to as image data) is processed by the read image processing unit 1033, and the density is calculated based on the appearance ratio of the margin part and the dot part. The read image processing unit 1033 detects a decrease in density by comparing the calculated density with the original image of the test pattern image. In addition, the read image processing unit 1033 observes the appearance of dots that should appear uniformly distributed with respect to white spots, and detects a white area where the appearance frequency of the dots is lower than other areas. To do. In this way, the read image processing unit 1033 detects image defects such as a decrease in density and white spots based on the result of scanning the test pattern image and the original image of the test pattern image.

  When the read image processing unit 1033 detects an image defect, the operation unit 1014 may notify a message prompting replacement of the cartridge 5 or may notify a message that the output cannot be guaranteed. In addition, when the life is reached in the life detection control, the replacement of the cartridge 5 may be notified only when the defective image is detected without notifying the replacement of the cartridge 5.

  In the first embodiment, when there is a request for image diagnosis, considering the life of other cartridges 5 as well, the same applies to cartridges that are nearing the end of their lifespan and cartridges 5 that are still used after notifying the end of life. Operate to perform diagnostic imaging. At this time, with respect to the test pattern image output on one sheet of paper P, a plurality of test pattern images are combined and output, and image diagnosis for a plurality of cartridges 5 is executed substantially simultaneously while suppressing a decrease in performance. It becomes possible. This is also effective when a plurality of cartridges 5 request diagnosis at substantially the same time.

  As the paper P used for the image diagnosis, the paper P set in the paper feed cassette 13 is used. Therefore, the width and length of the test pattern image must be sized according to the size of the paper P. Here, the size corresponding to the paper P means a size corresponding to an area where image formation is possible on the paper P excluding the upper, lower, left and right margins. As described above, the length in the conveyance direction of the test pattern image of the image diagnosis executed in the first embodiment is 85 mm. The paper P set in the paper feed cassette 13 has a length in the transport direction of 279 mm. That is, three test pattern images can be arranged on the paper P in the transport direction. Therefore, in addition to the cartridge 5 for which image diagnosis is requested, a test pattern image can be output to one sheet P up to two cartridges 5, and image diagnosis for three cartridges 5 can be executed. . In the first embodiment, the cartridge 5 to be subjected to image diagnosis at the same time is selected from the cartridges 5 in which the remaining amount of toner or the life information of the photosensitive drum 1 is not more than a predetermined value. When the number of cartridges 5 whose lifetime information is equal to or less than a predetermined value is greater than the number of outputtables (3 in the above-described example), the cartridge 5 closer to the end of lifetime is preferentially selected. Since the cartridge 5 near the end of its lifetime has been used for a longer period, there is a high possibility that an image defect will occur. For this reason, image diagnosis is performed with priority given to these to prevent image defects from occurring in a normal printing operation. The test pattern image corresponding to the cartridge 5 selected in this way is arranged according to the size of the paper P, and is set as a test pattern image output on one paper P.

  An example of selecting a test pattern image when the life information of each cartridge 5 is shown in Table 1 will be described.

表１で、１列目は各色を示し、２列目は各色のトナー残量（％）を示し、３列目は各色の感光ドラム１の寿命（ドラム寿命（％））を示す。いずれも、上述した方法で、交換部品管理部２０４０によって算出される。

In Table 1, the first column shows each color, the second column shows the remaining amount of toner (%) of each color, and the third column shows the life (drum life (%)) of the photosensitive drum 1 of each color. Both are calculated by the replacement part management unit 2040 by the method described above.

  When the calculated remaining toner amount and the life of the photosensitive drum 1 are in the state shown in Table 1, the replacement part management unit 2040 notifies the controller control unit 1010 of the life information because the remaining toner amount of the cartridge 5Y is 0%. At the same time, image diagnosis for the cartridge 5Y is requested. In response to a request for image diagnosis from the replacement part management unit 2040, the test pattern image generation unit 1042 generates a test pattern image using the test pattern image generation unit 1042. The test pattern image generation unit 1042 first arranges a Y test pattern image that is a target of a diagnosis request. Then, the test pattern image generation unit 1042 refers to each cartridge information in Table 1 and determines whether there is a cartridge 5 whose lifetime information is 10% or less. For example, in the case of Table 1, the test pattern image generation unit 1042 determines that image diagnosis is performed on the cartridge 5C because the drum life of the cartridge 5C is 5% and the toner remaining amount and the drum life of the cartridge 5K are 7%. Then, C and K test pattern images are generated. As described above, the order of the cartridges 5 to be subjected to image diagnosis (hereinafter referred to as priority order) is determined based on the life of the cartridge 5, and a test pattern image suitable for the cartridge 5 is output according to the priority order. Arrange in order. In the above-described example, the priority is the cartridge 5C for the first and the cartridge 5K for the second, except for the cartridge 5Y that is the target of the image diagnosis request.

  The test pattern image generated by the test pattern image generation unit 1042 in this way is shown in FIG. As shown in FIG. 3, the test pattern images for the three YCK cartridges 5Y, 5C, and 5K generated by the test pattern image generation unit 1042 are sequentially arranged from the top in the paper P conveyance direction. Further, for example, when the remaining amount of toner in the cartridge 5C is greater than 10% with respect to the life information, the test pattern images of only Y and K are arranged on the paper P. Further, in addition to the cartridges 5Y, 5C, and 5K, when the remaining amount of toner in the cartridge 5M is 10% or less, since only three test pattern images can be arranged on the paper P, they are arranged as follows. The That is, two cartridges 5 are selected in order from the cartridge 5 closer to 0% among the cartridges 5M, 5C, and 5K, and a test pattern image for the color of the selected cartridge 5 is arranged. As described above, in the first embodiment, the image diagnosis can be performed with a smaller number of sheets P (one sheet in FIG. 3) than the number of image diagnoses (three in the example in FIG. 3).

  When selecting the cartridge 5 to be subjected to image diagnosis, the priority order is determined based on the life information, but the selection method is not limited to this. For example, the priority order may be determined by the user's designation, or if the image diagnosis has been executed before, the color having the longest interval since the previous image diagnosis may be given priority. In addition, as for the paper P used for image diagnosis, a test pattern image to be executed may be first placed without considering the size of the paper P, and the paper P having a length corresponding to the created test pattern image may be set. . Further, when the use of the cartridge 5 is continued after the remaining amount of toner reaches 0%, the following may be performed. When image diagnosis is requested for the cartridge 5 that has been used even after the remaining amount of toner reaches 0%, image diagnosis is requested again when the number of prints after image diagnosis reaches a predetermined value. For example, it may be operated so that image diagnosis can be executed at regular intervals.

<Image diagnosis processing>
FIG. 4 is a flowchart showing how the controller control unit 1010 controls when an image diagnosis request is received from the engine control unit 2010. In step (hereinafter referred to as S) 100, the controller control unit 1010 receives an image diagnosis execution request from the engine control unit 2010. In step S101, the controller control unit 1010 acquires information about the paper P set in the paper cassette 13, that is, the size of the paper P, and determines the size of the output image that can be output as a test pattern image based on the size of the paper P. To do. In step S102, the controller control unit 1010 first selects a test pattern image for the cartridge 5 that is the target of the image diagnosis request as a test pattern image. The controller control unit 1010 arranges a test pattern image suitable for the cartridge 5 that is the target of the image diagnosis request on the output image for forming the test pattern image on the paper P. For example, in the case of the state shown in Table 1, the controller control unit 1010 selects a test pattern image for the cartridge 5Y that is the object of the image diagnosis request, and arranges it at the leading edge of the paper P as shown in FIG. In S103, the controller control unit 1010 arranges a test pattern image for another cartridge 5 after the test pattern image is arranged in the output image, and there is still a free area for the output image size determined in S101. It is determined whether or not it is possible. If the controller control unit 1010 determines in step S103 that a test pattern image for another cartridge 5 can be arranged, the process proceeds to step S104. If the controller control unit 1010 determines in step S103 that a test pattern image for another cartridge 5 cannot be arranged, the process proceeds to step S108.

  In step S <b> 104, the controller control unit 1010 selects one cartridge 5 for the other cartridges 5 (unselected cartridges 5) in the order of the calculated lifetime being low (low remaining). For example, in the case of the state shown in Table 1, the controller control unit 1010 selects the cartridge 5C having a drum life of 5% from the three of M, C, and K. In step S105, the controller control unit 1010 determines whether the cartridge 5 selected in step S104 is a target of image diagnosis based on the life information based on whether the life state is a predetermined value or less. If the controller control unit 1010 determines in step S105 that the life state of the cartridge 5 selected in step S104 is equal to or less than a predetermined value and determines that the cartridge 5 is a target of image diagnosis, the process proceeds to step S106. In step S106, the controller control unit 1010 sets the cartridge 5 selected in step S104 as a target of image diagnosis, and adds a test pattern image for the cartridge 5 as an output image. For example, in the case of the state shown in Table 1, since the selected cartridge 5C has a life state (drum life) of 10% or less, the controller control unit 1010 determines that it is a target of image diagnosis and performs a test on the cartridge 5C. A pattern image is added to the output image (see FIG. 3). If the controller control unit 1010 determines in step S105 that the life state of the cartridge 5 selected in step S104 is not equal to or less than the predetermined value and determines that the cartridge 5 is not a target for image diagnosis, the process proceeds to step S107. As described above, the controller control unit 1010 determines the size of the output image based on the size of the paper P, and the test pattern image is output to the output image based on the size of the output image and the test pattern image used for image diagnosis. Place.

  In step S <b> 107, the controller control unit 1010 determines whether all the cartridges 5 have been selected as determination targets for whether or not to be image diagnosis targets. If the controller control unit 1010 determines in step S107 that all the cartridges 5 have not been selected, the process returns to step S103. If the controller control unit 1010 determines that all the cartridges 5 have been selected in S107, the process proceeds to S108. The controller control unit 1010 repeats the processing from S103 to S106 until it determines that it is impossible to arrange the test pattern image with respect to the outputable image size determined in S101, or until all the cartridges 5 are selected. For example, in the case of the state shown in Table 1, the output image has an empty area, and the cartridge 5K is determined to be the target of image diagnosis, and a test pattern image for the cartridge 5K is added to the output image (see FIG. 3). Here, the cartridge 5M is not selected, but since there is no empty area in the output image determined in S101 (see FIG. 3), the controller control unit 1010 advances the process to S108. According to Table 1, since the lifetime of the cartridge 5M is not less than the predetermined value (10%), even if there is an empty area in the output image, it is not a judgment target for image diagnosis.

  In step S <b> 108, when the test pattern image to be formed on the paper P is determined, the controller control unit 1010 outputs a test pattern image print instruction to the engine control unit 2010. When the engine control unit 2010 receives a test pattern image print instruction from the controller control unit 1010, the engine control unit 2010 forms a test pattern image on the paper P and conveys the paper P to the image reading unit 2050. In step S109, the controller control unit 1010 determines whether reading of the test pattern image formed on the paper P by the image reading unit 2050 is completed. The controller control unit 1010 determines whether reading of the test pattern image by the image reading unit 2050 has been completed based on the notification from the engine control unit 2010. If the controller control unit 1010 determines in step S109 that reading of the test pattern image on the paper P by the image reading unit 2050 has not been completed, the process returns to step S109. If the controller control unit 1010 determines in step S109 that reading of the test pattern image on the paper P by the image reading unit 2050 has been completed, the process proceeds to step S110.

  In step S110, the controller control unit 1010 acquires the result of reading the test pattern image on the paper P by the image reading unit 2050 from the engine control unit 2010. In step S <b> 111, the controller control unit 1010 determines whether the read image determination unit 1041 has an image defect (whether image defect has occurred) from the read result acquired in step S <b> 110. In step S112, the controller control unit 1010 determines whether an image defect has occurred as a result of the determination in step S111. For example, in the case of the state shown in Table 1, since the test pattern images are formed for the cartridges 5Y, 5C, and 5K as shown in FIG. 3, the controller control unit 1010 generates an image defect for each of the cartridges 5Y, 5C, and 5K. Determine whether or not. If the controller control unit 1010 determines in S112 that an image defect has occurred, the process proceeds to S113, and if it is determined that no image defect has occurred, the process ends. In step S <b> 113, the controller control unit 1010 notifies the user of replacement of the cartridge 5 determined to have an image defect from the operation unit 1014, and ends the process.

  As described above, in the first embodiment, the test pattern images are arranged and executed up to the maximum number that can be arranged on the paper P. Therefore, it is possible to execute image diagnosis by outputting only the necessary test pattern images without increasing the number of output sheets of paper P. Further, since the target to be executed is changed every time the image diagnosis is executed according to the priority order, the image diagnosis desired to be given priority at the time of executing the image diagnosis can be appropriately executed.

  In the first embodiment, the method of performing the image diagnosis to determine the deterioration of the toner by the image analysis focusing on the density of the image and to determine the replacement of the cartridge 5 has been described. However, not only the toner but also replacement parts that are subject to aging such as the photosensitive drum 1, the intermediate transfer belt 8, the fixing roller 18 and the pressure roller 19 of the fixing device 17, and the rollers such as the paper feeding roller 14 of the feeding and conveying device 12 On the other hand, the present invention is applicable. For each replacement part, an algorithm for analyzing a symptom (hereinafter referred to as an image symptom) about a characteristic image generated according to a secular change may be prepared. Further, not only image diagnosis for detecting the aging state of replacement parts, but also image diagnosis for detecting characteristic image symptoms and the like caused by poor mounting at the time of component replacement may be performed. Furthermore, as a result of the image diagnosis, in addition to notifying the user to replace the image, the image forming process and the correction process may be performed on the operation of the printer according to the result of the image diagnosis.

  In the first embodiment, the image forming apparatus is described using a color laser printer. However, the present invention is also applicable to printing apparatuses having other configurations such as a monochrome laser printer and an inkjet printer. In the first exemplary embodiment, the image reading apparatus is provided in the double-sided conveyance path. However, the configuration is not limited to this configuration as long as the printed paper can be scanned. Even if it is not configured to be installed on the paper conveyance path, it has a separate document reading device, such as a copier, for example, and the paper P on which the test pattern image is formed by the image forming device is set in the separate document reading device. You may obtain it by scanning.

  As described above, according to the first embodiment, when an image defect or the like is detected, the test pattern image can be efficiently arranged on the recording material without reducing the detection accuracy.

  In the first embodiment, a configuration in which a plurality of test pattern images are arranged only in the length direction in which the test pattern images are output has been described. In the second embodiment, a configuration in which the test pattern images are combined more suitably in consideration of the size of the test pattern image and the position where the test pattern image is arranged is shown. In the second exemplary embodiment, in addition to the image defect due to the secular change of the cartridge 5, the image defect due to the sheet P passing through the fixing device 17 and the surface of the fixing roller 18 being scraped, and the wear of the paper feed roller 14. And image defects caused by adhesion of paper dust and the like are detected.

<Block diagram>
This is as shown in FIG. The replacement part management unit 2040 calculates and holds the life information of the fixing roller 18 and the paper feed roller 14 in addition to the cartridge 5. As with the life of the photosensitive drum 1, the life information is calculated by monitoring the driving state of each roller by monitoring the driving state of each roller, and calculating the ratio with respect to the assumed rotation distance.

<Replacement parts status and diagnostic imaging>
In the image diagnosis for the fixing roller 18, in order to find the scraping that occurs near the end of the sheet P being conveyed, the positions of both ends (L) and right (R) of the left side (L) with respect to the width direction of the sheet P ( Test pattern images are formed on both ends. In the second embodiment, for example, a 20% monochromatic halftone image having a width of 40 mm is formed on both ends of the paper P, and white spots where no image is formed due to surface scraping are detected. FIG. 5A shows the arrangement of the test pattern image with respect to the fixing roller 18. This test pattern image is an image having a margin of 132 mm (= 66 mm + 66 mm) in the center in the width direction, and at least a part of this image needs to be formed on the paper P in order to perform image diagnosis. For this reason, it is necessary to perform image diagnosis using a paper P having a paper width that allows the test pattern images at both ends to be formed with a predetermined width or more. The image length is 95 mm, which is longer than one rotation (90 mm) of the fixing roller 18. A test pattern image suitable for the fixing roller 18 is a test pattern image in which a position in the output image is designated.

  The paper feed roller 14 is disposed at the front end center position (tip end, center) of the paper stacking portion of the paper feed cassette 13. The paper feed roller 14 presses and abuts against a bundle of sheets P (hereinafter referred to as a sheet bundle) when feeding, thereby separating and transporting the uppermost sheet P of the sheet bundle. Used for. The test pattern image is formed at a position where the paper feed roller 14 contacts the paper P. FIG. 5B shows the arrangement of the test pattern image with respect to the paper feed roller 14. The test pattern image has a width of 50 mm at the center end position in the width direction of the paper P, and the image length is set to 65 mm by securing one round (62 mm) of the paper feed roller 14. The test pattern image suitable for the paper feed roller 14 is a test pattern image in which a position in the output image is designated. The test pattern image is intended to output a solid image of a single color and detect transfer defects due to adhesion of paper dust or the like. This single-color test pattern image is desirably executed with K output for ease of image defect detection, but the present invention is not limited to this, and other colors may be used.

  An example of selecting a test pattern image when each piece of life information is shown in Table 2 is shown.

表２の（ａ）に示すカートリッジ５の寿命情報は実施例１の表１と同様であり、説明を省略する。表２の（ｂ）は、定着ローラ１８及び給紙ローラ１４の寿命情報（％）である。表２（ｂ）は、１列目に各部材名を示し、２列目に各部材の寿命（％）を示す。実施例１と同様に、画像診断が要求されたカートリッジ５Ｙと寿命の少ない交換部品から順番にテストパターン画像が配置される。なお、カートリッジ５に適したテストパターン画像は、出力画像における位置が指定されていないテストパターン画像である。表２の場合、寿命が０％となっているカートリッジ５Ｙが画像診断要求の対象であり、最初に選択される。カートリッジ５Ｙの次に選択されるのは、表２（ｂ）に示す給紙ローラ１４（寿命４％）である。給紙ローラ１４のテストパターン画像は、図５（ｂ）に示したように用紙Ｐの先端に配置する必要がある。このため、テストパターン画像の配置は、まず出力画像の先端に給紙ローラ１４用のテストパターン画像が配置され、次いでカートリッジ５Ｙ用のテストパターン画像（他の検査用画像）が配置される。次に残りの寿命が短いカートリッジ５Ｃのテストパターン画像が配置される。このように、出力画像に各テストパターン画像を配置することで、実施例１と同じく、搬送方向に対しては新たにテストパターン画像を配置することができなくなる。しかし、定着ローラ１８のテストパターン画像は、図５（ａ）に示したように用紙Ｐの両端部に配置する構成であり、給紙ローラ１４の用紙中央部に配置するテストパターン画像と組み合わせることが可能である。

The life information of the cartridge 5 shown in (a) of Table 2 is the same as that of Table 1 of Example 1, and the description is omitted. (B) in Table 2 shows the life information (%) of the fixing roller 18 and the paper feed roller 14. Table 2 (b) shows the name of each member in the first column, and the life (%) of each member in the second column. As in the first embodiment, test pattern images are arranged in order from the cartridge 5Y for which image diagnosis is required and the replacement parts with a short life. Note that the test pattern image suitable for the cartridge 5 is a test pattern image in which the position in the output image is not specified. In the case of Table 2, the cartridge 5Y whose lifetime is 0% is the object of the image diagnosis request, and is selected first. Next to the cartridge 5Y, the paper feed roller 14 (life 4%) shown in Table 2 (b) is selected. The test pattern image of the paper feed roller 14 needs to be arranged at the leading edge of the paper P as shown in FIG. For this reason, the test pattern image is arranged such that a test pattern image for the paper feed roller 14 is first arranged at the leading end of the output image, and then a test pattern image for the cartridge 5Y (another inspection image) is arranged. Next, a test pattern image of the remaining cartridge 5C having a short lifetime is arranged. As described above, by arranging each test pattern image in the output image, it becomes impossible to newly arrange a test pattern image in the transport direction as in the first embodiment. However, the test pattern image of the fixing roller 18 is configured to be disposed at both ends of the sheet P as shown in FIG. 5A, and is combined with the test pattern image disposed at the center of the sheet of the sheet feeding roller 14. Is possible.

  A test pattern image arranged in this way is shown in FIG. As shown in FIG. 6, first, a test pattern image for the paper feed roller 14 that needs to be arranged at the center of the front end of the paper P is arranged, and a fixing roller that can be combined with the test pattern image for the paper feed roller 14. Test pattern images for 18 are arranged at both left and right ends. Subsequently to these test pattern images, test pattern images for the cartridge 5Y and the cartridge 5C are arranged in the transport direction. From the above, a test pattern image necessary for image diagnosis of the four replacement parts of the paper feed roller 14, the fixing roller 18, and the cartridges 5Y and 5C can be formed on one sheet of paper P. As described above, also in the second embodiment, the image diagnosis can be performed with the number of sheets P (one sheet in FIG. 6) smaller than the number of image diagnosis (four in the example in FIG. 6).

<Image diagnosis processing>
FIG. 7 is a flowchart showing a state of control of the controller control unit 1010 when an image diagnosis request is received from the engine control unit 2010. The processes of S200 and S201 are the same as the processes of S100 and S101 of FIG. In step S202, the controller control unit 1010 first selects a test pattern image for the replacement part that is the target of the image diagnosis request in step S201, and places the test pattern image in the output image. For example, in the state shown in Table 2, since the remaining amount of toner in the cartridge 5Y is 0%, the controller control unit 1010 places a test pattern image for the cartridge 5Y in the output image. In step S <b> 203, the controller control unit 1010 selects one replacement part that has not yet been selected in the order of low life information. In step S <b> 204, the controller control unit 1010 determines whether the selected replacement part is a target of image diagnosis based on whether the life state is equal to or less than a predetermined value. If the controller control unit 1010 determines in S204 that the life state is less than or equal to the predetermined value, the process proceeds to S205, and if it is determined that the life state is greater than the predetermined value, the process proceeds to S210. For example, in the case of Table 2, since the paper feed roller 14 having the next lowest life information after the cartridge 5Y is selected and the life of the paper feed roller 14 is 4%, which is less than a predetermined value (10%), the paper feed roller 14 is an object of image diagnosis.

  In step S205, the controller control unit 1010 determines whether or not the placement position of the test pattern image for the replacement part selected in step S203 is not designated, or whether or not a test pattern image placed in the designated position already exists. To check. Hereinafter, the designated arrangement position of the test pattern image is referred to as a designated position. In step S205, the controller control unit 1010 determines that the placement position is specified for the test pattern image of the replacement part in the life state equal to or less than the predetermined value selected in step S203, and that another test pattern image already exists at the specified position. If so, the process proceeds to S206. For example, in the case of Table 2, the test pattern image for the paper feed roller 14 has a designated position (the center leading end position of the output image), and the test pattern image for the cartridge 5Y is currently at that position. In step 1010, the process proceeds to step S206. In step S206, the controller control unit 1010 determines whether or not the position of the test pattern image that has already been arranged can be changed for the test pattern image that has already been arranged at the designated position.

  If the controller control unit 1010 determines in step S206 that the position of the test pattern image that has already been arranged can be changed, the process proceeds to step S207. If the controller control unit 1010 determines that it cannot be changed, the process proceeds to step S210. . For example, in the case of Table 2, since there is no designated position in the test pattern image for the already arranged cartridge 5Y, the controller control unit 1010 determines that the position can be changed. In step S207, the controller control unit 1010 changes (moves) the position of the test pattern image that has already been arranged (already installed). For example, in the case of Table 2, the controller control unit 1010 moves the test pattern image for the cartridge 5Y to the rear end side of the output image while ensuring a vacant area where the test pattern image for the paper feed roller 14 can be arranged. And the process proceeds to S208.

  If the controller control unit 1010 determines in step S205 that there is no designation at the placement position of the test pattern image or there is no other test pattern image at the designated position, the process proceeds to step S208. In step S208, the controller control unit 1010 determines whether it is possible to place the test pattern image for the replacement part selected in step S203 in the empty area of the output image. If the controller control unit 1010 determines in step S208 that the test pattern image can be arranged in the empty area of the output image, the process proceeds to step S209. If it is determined that the test pattern image is not possible, the process proceeds to step S210. In step S209, the controller control unit 1010 newly arranges a test pattern image for the replacement part selected in step S203 in the empty area. It should be noted that the “empty area of the output image” when the process proceeds from S207 to S208 is an empty area obtained by moving the test pattern image already arranged in S207. For example, in the above-described example, the test pattern image for the cartridge 5Y is first arranged at the front end of the paper P in S202. However, since the test pattern image for the paper feed roller 14 selected in S203 is designated to be positioned at the center front end of the paper P, the position of the test pattern image for the cartridge 5Y that has no particular designated position is changed. The Then, a test pattern image for the paper feed roller 14 is arranged in the empty area.

  In step S210, the controller control unit 1010 determines whether all replacement parts have been selected. If the controller control unit 1010 determines in S210 that all replacement parts have not been selected, the process returns to S203, and if it is determined that all replacement parts have been selected, the process proceeds to S211. As described above, S203 to S209 are performed on all the replacement parts, and the test pattern image to be output is determined.

  For example, in the case of Table 2, since the cartridge 5C is selected as the replacement part with the next lowest life state, and the life state of the cartridge 5C is equal to or less than a predetermined value (5% ≦ 10%), it is determined that it is an object of image diagnosis. Is done. The test pattern image for the cartridge 5C does not have a designated position, and the output image still has a free area, and therefore is arranged following the test pattern image for the cartridge 5Y (see FIG. 6). Further, the cartridge 5K is selected as the replacement part with the next lowest life state and is determined to be the target of image diagnosis, but there is no empty area in the output image in which the test pattern image for the cartridge 5K is arranged. For this reason, the test pattern image for the cartridge 5K is not added to the output image. Further, the fixing roller 18 is selected as a replacement part having the next lowest life state, and is determined to be an object of image diagnosis. The test pattern image for the fixing roller 18 has designated positions (both ends of the output image), and the test pattern image for the fixing roller 18 and the test pattern image for the paper feed roller 14 can be arranged in combination. Therefore, the test pattern image for the fixing roller 18 is added to the output image (see FIG. 6).

  Note that the processing from S211 to S215 is the same as the processing from S108 to S112 of FIG. In step S <b> 216, the controller control unit 1010 notifies the user of information for urging replacement of the replacement part determined to have an image defect in step S <b> 215 from the operation unit 1014.

As described above, the test pattern image corresponding to the type of image diagnosis can be more effectively arranged with the test pattern image formed on the paper P by using the information regarding the size and position designation. Image diagnosis can be performed efficiently.
As described above, according to the second embodiment, when an image defect or the like is detected, the test pattern image can be efficiently arranged on the recording material without reducing the detection accuracy.

5Y, 5M, 5C, 5K Cartridge 1010 Controller control unit 1041 Read image determination unit 1042 Test pattern image generation unit

Claims (17)

An image forming apparatus including an image forming unit that forms an image for inspection for inspecting an image forming state on a recording material,
A control means for controlling the position of the inspection image so as to generate a plurality of types of the inspection images and disposing the generated inspection images in a region where an image can be formed on a recording material;
The control means determines the size of the region based on the size of the recording material, and arranges the inspection image in the region based on the size of the region and the size of the inspection image. Image forming apparatus. Reading means for reading the inspection image formed on the recording material;
Diagnosing means for diagnosing an image defect based on the result of reading the inspection image by the reading means;
The image forming apparatus according to claim 1, further comprising: With replacement parts that are replaced when they reach the end of their lives,
The diagnosis means performs a diagnosis as to whether or not an image defect due to the life of the replacement part has occurred,
The image forming apparatus according to claim 2, wherein the control unit generates an inspection image suitable for diagnosing whether or not an image defect due to a life of the replacement part has occurred. A plurality of the image forming units;
The image forming unit includes at least a photosensitive member carrying an electrostatic latent image, and developing means for developing the electrostatic latent image on the photosensitive member with toner,
The replacement part is the image forming unit,
The image forming apparatus according to claim 3, wherein the diagnosis unit diagnoses whether an image defect due to a lifetime of the image forming unit has occurred. A calculating unit that calculates the life of the image forming unit based on the degree of wear of the photoconductor or the remaining amount of toner in the developing unit;
The control unit determines a rank of the image forming units to be diagnosed based on lifetimes of the plurality of the image forming units calculated by the calculating unit, and the image according to the determined rank The image forming apparatus according to claim 4, wherein the inspection images corresponding to the forming unit are sequentially arranged in the region.   The said calculating means calculates the remaining amount of the toner based on the number of pixels having a density equal to or higher than a predetermined value in an image input when the image forming unit performs image formation. The image forming apparatus described in 1.   The image forming apparatus according to claim 6, wherein the calculation unit calculates a degree of wear of the photoconductor based on a cumulative number of rotations of the photoconductor.   An inspection image used for diagnosing whether or not an image defect due to the life of the photosensitive member has occurred has a length corresponding to at least one turn of the photosensitive member in a recording material conveyance direction. The image forming apparatus according to any one of claims 4 to 7.   The image forming apparatus according to claim 4, wherein the inspection image includes an inspection image in which a position in the region is designated.   The control means may arrange the other inspection image at the designated position when the examination image with the designated position is arranged at the designated position of the region. When the position of the inspection image is not specified, the other inspection image is moved to secure a free area, and the inspection image having the specified position is arranged in the free area. The image forming apparatus according to claim 9. A paper feed roller for feeding the recording material stored in the paper feed unit;
Fixing means for fixing the inspection image formed on the recording material;
With
The replacement part is the paper feed roller and / or the fixing unit,
The image forming apparatus according to claim 9 or 10, wherein the diagnosis unit diagnoses whether or not an image defect due to a life of the sheet feeding roller and / or the fixing unit has occurred. apparatus.   An inspection image used for diagnosing whether or not an image defect due to the life of the paper feed roller has occurred has a length of at least one circumference of the paper feed roller in the recording material conveyance direction, The image forming apparatus according to claim 11, wherein the image forming apparatus is disposed at a front end portion of the region in the transport direction and a central portion in a direction orthogonal to the transport direction.   An inspection image used for diagnosing whether or not an image defect due to the lifetime of the fixing unit has occurred has a length of at least one round of the fixing unit in the transport direction, and The image forming apparatus according to claim 12, wherein the image forming apparatus is disposed at both ends in a direction orthogonal to the transport direction.   When the object of diagnosis is the paper feed roller and the fixing unit, the control unit combines the inspection image suitable for the paper feed roller and the inspection image suitable for the fixing unit in the region. The image forming apparatus according to claim 13, wherein the image forming apparatus is disposed on the screen.   15. The image forming apparatus according to claim 11, wherein the reading unit reads the inspection image after being fixed by the fixing unit.   The said control means produces | generates the image for a test | inspection suitable for the said replacement part in which the lifetime of the said replacement part is below a predetermined value, The Claim 1 characterized by the above-mentioned. Image forming apparatus.   The control unit does not arrange the inspection image in the area when there is no empty area in which the inspection image is arranged in the area. The image forming apparatus described in 1.

Images